1:45 PM | **Strong-to-severe thunderstorms on the table in the Mid-Atlantic region from late tomorrow into tomorrow night**
Paul Dorian
The 12Z NAM surface forecast map for late tomorrow evening indicates heavy rainfall is on the table in the Mid-Atlantic region as a cool front pushes through the area. Map courtesy NOAA, tropicaltidbits.com
Overview
Several ingredients will come together late tomorrow and tomorrow night to produce the chance of strong-to-severe thunderstorm activity in the Mid-Atlantic region. The combination of an approaching cool front, higher heat and humidity, a strong low-level jet, and an upper-level trough will likely result in showers and thunderstorms from later tomorrow into tomorrow night and any storm can reach strong-to-severe levels. The main threat should be damaging wind gusts; however, given the expected strong wind shear, there will also be the potential of isolated tornadoes; especially, over northeast PA and NW NJ.
One ingredient later tomorrow that will enhance the chance of severe weather in the Mid-Atlantic region will be a strong upper-level trough that will act to significantly increase upward motion in the atmosphere. Map courtesy NOAA, tropicalltidbits.com
Details
There were thunderstorms in the Mid-Atlantic region this past weekend – some of which were strong-to-severe – but not everyone was hit as they were scattered in nature. Those locations that were not hit by storms this past weekend will be threatened again later tomorrow and tomorrow night as a combination of ingredients come together. To begin, dew points are likely to climb to near 70 degrees later tomorrow as a southwesterly flow of air forms in the Mid-Atlantic region (dew points today were confined to the very comfortable upper 40’s and lower 50’s). An upper-level trough of low pressure will head this way from the Great Lakes and it’ll act to enhance upward motion - a key ingredient in the formation of showers and thunderstorms. In addition, winds in the lower part of the atmosphere (e.g., 850 mb level) will become increasingly strong later tomorrow and feature directional and speed shear which will increase the chance of isolated tornadoes; especially, across portions of the northern Mid-Atlantic region (e.g., NE PA, NW NJ).
A strong low-level jet on Wednesday evening will contribute to directional and speed wind shear and this ingredient could lead to isolated tornadoes in portions of the Mid-Atlantic region. Map courtesy NOAA, tropicaltidbits.com
In terms of rainfall, any storm that forms later tomorrow/tomorrow night will have the capability of producing heavy rainfall given the amount of available moisture and the lifting required in the atmosphere. The timetable for this potential severe weather event in the Mid-Atlantic region is late afternoon across central portions of the Mid-Atlantic (e.g., central PA) and likely the later evening hours across the I-95 corridor and points east from there to the coast. The surface cool front will move offshore by early Thursday morning paving the way for lowering humidity later in the day to go along with decreasing cloud cover.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
Follow us on Facebook, Twitter, YouTube